Exceptional characteristics of heterotetrameric (α2β2) E1p of the pyruvate dehydrogenase complex from Zymomonas mobilis: expression from an own promoter and a lipoyl domain in E1β

Abstract

In the pyruvate dehydrogenase complex (PDHC) of Zymomonas mobilis the L subunit of the pyruvate dehydrogenase (E1p) as well as the acetyltransferase (E2p) contain an N-terminal lipoyl domain. Both lipoyl domains were acetylated in vitro using 2-14 C-pyruvate as a substrate, demonstrating that both lipoyl domains can accept acetyl groups from the E1 component. As previously shown the structural genes (pdhAKL, pdhB, lpd) encoding the pyruvate dehydrogenase complex of Z. mobilis are located in two distinct gene clusters, pdhAKL and pdhB-orf2-lpd (U. . Analysis of pdh gene expression using lacZ fusions revealed that the DNA fragments upstream of pdhAK, pdhB and lpd each have promoter activities. These pdh promoter activities were 7^30-fold higher in Z. mobilis than in Escherichia coli. ß 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

Recurrent intragenomic recombination leading to sequence homogenization during the evolution of the lipoyl-binding domain

“…Typically, the N‐terminal LBD is present in each E2 subunit. Duplications of the LBD in E2 and fusions of LBD with E1 and E3 subunits were previously discussed [4–8]. The LBDs are linked to each other and to the remaining parts of the corresponding proteins via long, flexible segments that are typically enriched in alanine, proline and charged residues.…”